The phosphatide antigen will be fractionated and further purified by the method described by Williams, et al. It is possible that purified fractions may be obtained which will be more potent than the original preparation we are using. Studies will also be initiated to determine if the route of injection of phosphatide into the animals influences tumor growth in mice injected with tumor cells by different routes. The various other fractions such as MER and waxes A, B and C will be tested for their influence on tumor growth. The observation that animals sensitized with BCG do not display delayed reactions to phosphatides indicates that the mechanism of resistance is not associated with delayed hypersensitivity. We will utilize Hibbs technique to determine if macrophages are activated by phosphatides to the same degree as they are following sensitization of C57B1/6 mice with BCG. Further studies of the effects of ALS, cortisone and SiO2 upon tumor growth in normal and immunized mice will be carried out.